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#1 |
初级会员
注册日期: 2009-05-13
年龄: 38
帖子: 1
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校正了一天了,就是找不到哪里错了
%BiLinear Transformation: %Butterworth Lowpass Filter Design %Digital Filter Specifications: wp=0.2*pi; % digital Passband freq in Hz ws=0.3*pi;%digital Stopband freq in Hz Rp=1;%Passband ripple in dB As=15;%Stopband attenuation in dB %Analog Prototype Specifications:Inverse map-ping for frequencies T=1;Fs=1/T;%Set T=1 OmegaP=(2/T)*tan(wp/2); OmegaS=(2/T)*tan(ws/2); ep=sqrt(10^(Rp/10)-1); Ripple=sqrt(1/(1+ep*ep)); Attn=1/(10^(As/20)); %Analog Butterworth Prototype Filter Calculation: [cs,ds]=afd_butt(OmegaP,OmegaS,Rp,As); %%***Butterworth Filter Order=6 %Bilinear transformation: [b,a]=bilinear(cs,ds,T); [C,B,A]=dir2cas(b,a) %%C=5.7969e-004 %%B=1.0000 2.0183 1.0186 %%1.0000 1.9814 0.9817 %%1.0000 2.0004 1.0000 %%A=1.0000 -0.9459 0.2342 %% 1.0000 -1.0541 0.3753 %% 1.0000 -1.3143 0.7149 % Plotting figure(1);subplot(1,1,1) [db,mag,pha,grd,w]=freqz_m(b,a); subplot(2,2,1);plot(w/pi,mag);title(‘Magnitude Response'); xlabel(‘frequency in pi units’);ylabel(‘|H|');axis([0,1,0,1.1]) set(gca,’XTickMode’,'manual','XTick',[0,0.2,0.3,1]); set(gca,'YTickmode','manual','YTick',[0,Attn,Ripple,1]);grid; subplot(2,2,3);plot(w/pi,db);title('Magnitude in dB'); xlabel('frequency in pi units');ylabel('decibels'); xis([0,1,-40,5]); set(gca,'XTickMode','manual','XTick',[0,0.2,0.3,1]); set(gca,'YTickmode','manual','YTick',[-50,-15,-1,0]);grid; set(gca,'YTickLabelMode','manual',’YTickLabels',['50';'15';'1';'0']) subplot(2,2,2);plot(w/pi,pha/pi);title('Phase Response') xlabel('frequency in pi units');ylabel('pi units'); xis([0,1,-1,1]); set(gca,'XTickMode','manual','XTick',[0,0.2,0.3,1]); set(gca,'YTickmode','manual','YTick',[-1,0,1]);grid subplot(2,2,4);plot(w/pi,grd);title('Group Delay') xlabel('frequency in pi units');ylabel('Samples'); xis([0,1,0,10]) set(gca,'XTickMode','manual','XTick',[0,0.2,0.3,1]); set(gca,'YTickmode','manual','YTick',[0:2:10]);grid; 运行后的提示 ??? Calculation: | Error: Incomplete or misformed expression or statement. |
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